The present invention relates to a magnetic head, more precisely relates to a magnetic head capable of efficiently radiating heat generated in an element for reproducing data and preventing overheat of the element.
These days, magnetic disk units having large memory capacity and high memory density are required. Further, precise and compact magnetic disk units are required. The element for reproducing date of a conventional magnetic head is shown in FIGS. 18A, 18B, 19A and 19B. FIG. 18A is a sectional view of a recording and reproducing section xe2x80x9cAxe2x80x9d of a slider 10 seen from a disk-side face thereof; FIG. 18B is a plan view of the slider 10 seen from the disk-side face; FIG. 19A is a sectional view of the writing and reproducing section xe2x80x9cAxe2x80x9d seen from a side face of the slider 10; FIG. 19B is a side view of the slider 10.
In FIGS. 18A and 19A, a symbol 12 stands for an ALTIC (Al2O3TiC) substrate which is a basic material of the slider 10; a symbol 14 stands for an alumina insulating layer; a symbol 16 stands for a lower shielding layer; a symbol 18 stands for an MR element layer, a symbol 20 stands for a lower magnetic pole; a symbol 22 stands for a coil for writing data; and a symbol 24 stands for an upper magnetic pole. Note that, the lower magnetic pole 20 acts as an upper shielding layer of an element for recording data.
In the conventional compact magnetic head, heat is generated in elements for reproducing and writing data and a problem of overheating the magnetic head is occurred. FIG. 20 is a plan view of the coil 22 for writing data. In the coil 22, a part xe2x80x9cBxe2x80x9d enclosed by an upper magnetic pole 24 is made compact so as to write data with high frequency. With this structure, in the part xe2x80x9cBxe2x80x9d, thickness of the coil 22 is made thinner and width of the coil 22 is made narrower. Therefore, in the conventional compact magnetic head, sectional area of the coil wire must be smaller, spaces between the coil wire must be narrower, so that the coil 22 is apt to be overheated. By overheating the coil 22, the wire of the coil 22 is apt to be broken and a span of life of the coil 22 is made shorter.
To prevent the overheat of the magnetic head, several methods have been invented. For example, sectional area of the coil wire other than a part enclosed by a magnetic pole is made broader and spaces between the coil wire other than said part is made wider; area of a lower magnetic pole is made broader to improve heat-radiativity (see Japanese Patent Gazette No. 62-128011); a non-magnetizable metal is made contact with an upper shielding layer so as to act as a heat sink (see Japanese Patent Gazette No. 9-167314); a heat radiating layer made of a non-magnetizable material is provided in an MR layer (see Japanese Patent Gazette No. 7-210829); an insulating layer of a lead element layer is made of a material having high heat conductivity, e.g., silicon, diamond-like-carbon (see Japanese Patent Gazette No. 6-223331); and an insulating layer of a lead element layer is made of a aluminum nitride having high heat conductivity (see Japanese Patent Gazette No. 6-274830).
However, the conventional methods have following disadvantages.
For example, in the case of making the sectional area of the coil wire broader and making the spaces between the coil wire wider, heat generated in the part of the coil enclosed by the magnetic pole cannot be effectively restricted. In the case of using the material having high heat conductivity for the insulating layer of the lead element layer, heat is conducted toward an upper face or a bottom face of the layers so the heat cannot be effectively radiated. Further, in the case of making the non-magnetizable metal contact with the upper shielding layer as the heat sink, another manufacturing step other than forming the coil for writing data is required.
The present invention has been invented to solve the disadvantages of the conventional magnetic heads.
An object of the present invention is to provide a magnetic head for a large-capacity magnetic disk unit, which is capable of improving heat radiativity and preventing overheat of the magnetic head.
To achieve the object, the present invention has following structures.
The magnetic head of the present invention comprises: a slider having a disk-side face; an element for reproducing data; a shielding layer; a coil for writing data; magnetic poles; a heat radiating layer for radiating heat generated in the magnetic head; and an insulating layer for electrically insulating the heat radiating layer, wherein the heat radiating layer is provided near the element or the coil without touching the element, the shielding layer, the coil and the magnetic poles, the heat radiating layer is made of a material whose heat conductivity is higher than that of the insulating layer, and an end of the heat radiating layer is exposed in the disk-side face of the slider.
Preferably, the heat radiating layer and the coil are formed in the same layer.
Further, the preferable heat radiating layer is made of a non-magnetizable material including at least Pt, Au, Ag, Cu, Co, Ni, Fe or Al. With this structure, heat radiativity and electric-magnetic converting property of the magnetic head can be improved.
In the present invention, the heat generated in the magnetic head can be effectively radiated from the heat radiating layer, so that rising temperature of the magnetic head can be restricted and overheat of the magnetic head can be prevented. Therefore, a reliable magnetic head for a large-capacity magnetic disk unit can be provided. Since the heat radiating layer is provided without touching the element, the shielding layer, the coil and the magnetic poles, the electric-magnetic converting property of the magnetic head is not badly influenced. Further, the heat radiating layer can be formed in a step of forming the element, so the magnetic head of the present invention can be manufactured by a system for manufacturing the conventional magnetic heads.